FIG. 1 depicts an air-bearing surface (ABS) view of a conventional read apparatus used in magnetic recording technology applications. The conventional read apparatus 10 includes shields 12 and 18, insulator 14, magnetic bias structures 16, and sensor 20. The read sensor 20 is typically a giant magnetoresistive (GMR) sensor or tunneling magnetoresistive (TMR) sensor. The read sensor 20 includes an antiferromagnetic (AFM) layer 22, a pinned layer 24, a nonmagnetic spacer layer 26, and a free layer 28. Also shown is a capping layer 30. In addition, seed layer(s) may be used. The free layer 28 has a magnetization sensitive to an external magnetic field. Thus, the free layer 28 functions as a sensor layer for the magnetoresistive sensor 20. The read sensor 20 typically has its top narrower than its bottom. Thus, the read sensor 20 has junction angle, a. The junction angle is typically fifty degrees, plus or minus fifteen degrees. The lower junction angles are desirable to reduce or prevent damage to the tunneling barrier layer 26 during fabrication and to account for redeposition that occurs during fabrication. The magnetic bias structures 16 are used to magnetically bias the free layer 28.
Although the conventional apparatus 10 functions, there are drawbacks. The trend in magnetic recording is to higher areal density recording. A lower track width (TW) is desired for such higher areal densities. In addition, a reduced shield-to-shield spacing (SS) is desired for higher density recording. However, at smaller track widths, the performance of the read sensor 20 may be adversely affected. For example, the volumes of the AFM layer 22, pinned layer 24 and free layer 28 are reduced at narrow track widths. The free layer 28 reduction in volume is exacerbated by the free layer 28 being narrower than remaining magnetic layers. Thus, the stability of the read sensor 20 and ability of the free layer 28 to function as a sensor layer are impaired. Because a narrow shield-to-shield spacing is also desired and because of the nature of the read sensor 20, the thickness of the layers 22, 24 and 28 may be desired to remain thin.
Accordingly, what is needed is a system and method for improving the performance of a magnetic recording read apparatus, particularly at higher areal densities.